EP3418010B1

EP3418010B1 - A functional assembly for an industrial machine, in particular for a robot, including an operative unit equipped with a safety cover

Info

Publication number: EP3418010B1
Application number: EP17177677.6A
Authority: EP
Inventors: Giorgio BECCIANI; Giovanni Di Stefano; Stefano ARDUINO
Original assignee: Comau SpA
Current assignee: Comau SpA
Priority date: 2017-06-23
Filing date: 2017-06-23
Publication date: 2019-09-18
Anticipated expiration: 2037-06-23
Also published as: BR102018012935B1; RU2018122241A3; RU2763908C2; CN109109000A; EP3418010A1; BR102018012935A2; ES2760947T3; CA3007241A1; US20180370047A1; KR102480626B1; CN109109000B; RU2018122241A; KR20190000824A; US11065772B2; MX2018007624A

Description

Field of the invention

The present invention relates to a functional assembly for an industrial machine, in particular for a robot, of the type comprising:

a support frame, provided with a flange for attaching to a robot wrist or other element of an industrial machine,
an operative unit, for example, a gripping tool or an operator tool, supported by said support frame,
a safety cover for said operative unit, which is carried by said support frame, defining a containment volume,
wherein said functional assembly can assume a first operative configuration, in which said safety cover surrounds and covers said operative unit and a second operative configuration, wherein said operative unit is at least partially outside the containment volume of said safety cover.

Prior art

A functional assembly of the type indicated above is described and illustrated in the document WO 2017/036690 A1 . In the known device of this document, an operative unit in the form of a gripping tool is carried by the wrist of a multi-axis manipulator robot. The gripping tool is surrounded by a safety cover and is movable between an extracted position for gripping a piece, and a retracted position in which it is received within the safety cover.
In recent times, industrial robots of the so-called "collaborative" type have been widely used, configured to operate in an open, non-enclosed environment, in which operators who carry out manual operations are also present. Of course, robots of this type must ensure the necessary degree of safety for operators and, for this reason, are provided with sensor systems capable of detecting when parts of the robot are too close or in contact with a foreign body, and in particular with an operator present in the same working area.
Therefore, the need to extend the same safety criteria to the end-effectors carried by collaborative robots is felt. The known solution indicated above is an example of an attempt in this direction, but it is not entirely satisfactory in terms of safety, functionality and constructive simplicity.
A functional assembly according to the preamble of claim 1 is known from DE 20 2013 105501 U1 . A similar solution is known from DE 10 2012 217764 A1 . A functional assembly of this type with a safety cover having a movable portion is also known from WO 2017/158120 A1 , which is prior art according to Article 54(3) EPC. WO2017/036732 A1 is also part of the prior art.

Object of the invention

The object of the present invention is that of producing a functional assembly of the type indicated above, which produces a very high degree of safety with regard to its use in an open environment accessible to operators who must perform manual operations in the same working area.
Another preferred object of the present invention lies in the fact that a functional assembly of the above-mentioned type is provided, the performance of which is not affected by the size of the safety cover it is equipped with.
Another preferred object of the invention is that of reaching the aforesaid objectives with a relatively simple, lightweight and low-cost structure.

Summary of the invention

In view of achieving one or more of the aforesaid objects, the invention is carried out by a functional assembly having the characteristics according to claim 1.
Thanks to the aforesaid characteristics, the functional assembly according to the invention is able to meet the necessary safety requirements; it does not have performances impaired by the presence of the safety cover, and is constructively simple and efficient during use.
According to another preferred characteristic, the operative unit of the invention is displaceable with respect to said support frame, at least in one transverse direction with respect to said main direction, so that said operative unit can be moved into close proximity to the boundaries of the footprint area in the plan of said movable portion of the safety cover. Thanks to the aforesaid characteristics, the safety cover of the functional assembly according to the invention does not constitute a limitation to the performance of the functional assembly. For example, in the case in which the operative unit is a gripping tool used to pick up pieces from a container, the size of the safety cover does not prevent the gripping tool from picking up pieces even located adjacent to the walls of the container. In the preferred embodiment, the aforesaid operative unit is movable with respect to said support frame in two auxiliary directions, orthogonal to each other, and orthogonal to said main direction. In another embodiment, said operative unit is also rotatable with respect to said support frame around an axis orthogonal to said main direction.
In the preferred embodiment, the functional assembly according to the invention is intended to be connected to the wrist of a multi-axis manipulator robot.
Compared to the solution disclosed in WO 2017/036690 A1 , in which the safety cover is stationary relative to the attachment flange of the robot, and it is the gripping tool that is movable with respect to the cover, the present invention has several advantages.
Firstly, in the assembly according to the invention, the main part subject to movement is the aforesaid movable part of the safety cover, which is a "collaborative" structure, i.e. equipped with sensors configured to detect the presence or closeness of an operator. This constitutes a substantial improvement in safety on the plane with respect to the aforesaid known solution, in which the main part subject to movement is a gripping tool which, in order to carry out gripping and unloading of the pieces, is required to come out from the cover. The gripping tool, due to its very nature, cannot have a collaborative structure, so that it always poses a danger for the operators located in the working area.
In the case of the assembly according to the invention, the main part subject to movement is a collaborative structure. Furthermore, the arrangement can be such so that the movable part of the collaborative cover is only carried to its raised position, with the operative unit exposed, when the entire assembly is in an area inaccessible to the operator, for example, within a picking-up container of the pieces.
A further advantage of the assembly according to the invention lies in the fact that the guiding and driving system of the movement of the safety cover is simpler and lighter with respect to a guiding and driving system of the gripping tool. Secondly, the present invention allows the provision, if desired, of an additional upward stroke of the movable portion of the safety cover, so that in its raised position, the movable portion can define an additional safety barrier extended upwards, above the working area.
Furthermore, in the case of the application of gripping of pieces in a container, the dimensions and the vertical stroke of the movable portion of the safety cover are preferably chosen according to the size of the pieces to be gripped, in such a way that once a piece is picked up, the cover can be lowered into a position in which the picked-up piece is contained within the safety cover. In this way, when the robot moves the functional assembly outside the pick-up container of the parts, the piece that is picked up cannot be a source of danger to the operators in the working area.

Detailed description of embodiments of the invention

Further characteristics and advantages of the invention will become apparent from the description that follows with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

- Figure 1 is a perspective view of an industrial robot provided with a functional assembly according to the present invention, in a first operative condition,
- Figure 2 is a perspective view of the robot of Figure 1, in a second operative condition,
- Figure 3 is a front perspective view of an embodiment of the functional assembly according to the invention, in which the safety cover has been removed,
- Figure 4 is a rear perspective view of the functional assembly of Figure 3, in which the safety cover has been removed,
- Figure 5 is a perspective view of the support frame forming part of the functional assembly of Figure 3,
- Figures 6 and 7 are perspective views of the fixed portion and the movable portion of the safety cover provided with the functional assembly of Figure 3,
- Figure 8 is a partially sectioned elevational view of the functional assembly of Figure 3, which also shows the fixed portion and the movable portion of the safety cover,
Figure 9 is a partially sectioned, rear elevational view of the functional assembly of Figure 3, where the safety cover has been removed,
- Figure 10 is a side and cross-sectional view of the functional assembly of Figure 3, which also shows the fixed portion and the movable portion of the safety cover,
- Figures 11, 12A, 12B and 13 are diagrams illustrating the principle of operation of embodiments of the present invention, and
- Figures 14-16 are diagrams illustrating the advantages of the invention.

The drawings show, by way of example, a functional assembly according to the invention, equipped with an operative unit in the form of a gripping tool, connected to the wrist of a multi-axis manipulator robot and usable for gripping pieces P arranged in a container CT.
In Figures 1 and 2, numeral 1 indicates, in its entirety, a multi-axis manipulator robot, comprising a base 100 and a chain of robot elements 101, 102, 103, 104 mutually articulated to each other, and terminating with a robot wrist 105 provided with a flange 106 for connecting a functional assembly according to the invention.
Of course, the structure and configuration of the robot 1 can be of any known type. For this reason, the constructive details of the robot 1, such as the motors that drive the movements of the various robot elements and the electronic control system of the robot are not described or illustrated here, also because the removal of these details from the drawings makes them more readily and easily understood.
It should also be noted that the functional assembly according to the invention can also be used in an industrial machine that is different from a multi-axis manipulator robot, such as a Cartesian manipulator robot or any other type of machine configured to move an operator tool.
The functional assembly of the invention is indicated, in its entirety, in Figures 1 and 2 with the reference numeral 2. The functional assembly comprises a support frame 3 rigidly connected to the attachment flange 106 of the robot wrist 105. The support frame 3 supports an operative unit, which is indicated, in its entirety, with reference numeral 4 (see also Figures 3, 4) and which, in the illustrated embodiment, is a gripping tool. It is well-understood that the invention is applicable to any other type of "end-effector", for example, a welding head, a staple head or any other type of tool or device, including opto-electronic vision devices.
The gripping tool 4 is surrounded and covered by a safety cover as indicated in its entirety in Figures 1, 2 by reference 5. Still according to the invention, the safety cover 5 comprises a fixed portion 5A rigidly connected to the support frame 3, and a movable portion 5B, which is movable with respect to the fixed portion 5A, and outside thereof, in a main direction A (Figures 1, 2).
According to a preferred embodiment, both portions 5A, 5B of the safety cover 5 have a sensorized outer coating provided with sensors, for example of the capacitive and/or piezoresistive type, configured for detecting the proximity and/or the contact with a foreign body. The details of the configuration and arrangement of these sensors are not described and illustrated here, since they may be of any known type.
However, in a preferred embodiment, each of the portions 5A, 5B of the safety cover has a structure of the type disclosed in European Patent Application EP 1 7167 114 , filed by the same Applicant, and still secret at the priority date of the present invention. According to the solutions proposed in that patent application, the sensorized cover comprises a plurality of active layers and passive layers including:

a support structure of rigid or semi-rigid material (for example metal or plastic material) having a predetermined shape,
a damping layer formed of elastically yielding material, associated with an outer side of the support structure,
a piezoresistive contact sensor above the damping layer, which includes a piezoresistive layer interposed between a lower electrically conductive layer and an upper electrically conductive layer,
a lower covering layer and an upper covering layer formed of electrically insulating material, between which the piezoresistive contact sensor is interposed,
a capacitive proximity sensor, arranged above the piezoresistive contact sensor, comprising a first electrically conductive layer and a second electrically conductive layer, between which an intermediate layer of electrically insulating material is arranged,
an outer coating layer above the capacitive proximity sensor, preferably formed with electrically insulating material.

Thanks to the design of the safety cover 5 with sensorized coating, the robot control system is able to automatically stop the robot whenever excessive closeness or contact with a foreign body is detected. This makes it possible to safely use the functional assembly even in an open, non-enclosed environment, in which there are operators in the vicinity of the robot.
Of course, for applications of this type, the robot 1 carrying the functional assembly is also preferably a "collaborative"-type robot, that is, configured to operate safely in an environment in which operators have access to. To this end, these robots are generally equipped with casings that surround the movable elements of the robot and which are equipped with a sensorized outer surface.
The movable portion 5B of the safety cover 5 of the functional assembly according to the invention is movable between a lowered position, in which the gripping tool 4 is completely covered and surrounded by the safety cover 5 and a raised position (Figure 2) in which the gripping tool protrudes beneath the cover 5, so that it can grip a piece P within the container CT without the cover 5 interfering with the picked-up piece P
Of course, in the present description and in the attached claims, the terms "raised" and "lowered" are used with reference to a vertical orientation of the main direction A. Obviously, if the robot orientates the functional assembly in order to change the main direction A so it is no longer vertical, the movement of the movable cover nevertheless follows the direction A and the movable portion 5B is, however, able to move between an extreme covered position of the tool 4 and an opposite extreme position, in which the tool 4 is uncovered.
During use, the movable lower portion 5B of the safety cover 5 is only raised when the functional assembly 2 moves within the container CT, as in this condition, contact between the gripping tool 4 and a foreign body (in particular an operator who is near the container CT) is excluded. The movable portion 5B is, instead, held in its lowered position when the functional assembly 2 is moved by the robot 1 into the area outside the container CT to ensure the necessary safety for the operators present in the same area.
Compared to the solution disclosed in WO 2017/036690 A1 , in which the safety cover is stationary relative to the attachment flange of the robot, and it is the gripping tool that is movable in the main direction A, the present invention has several advantages. Firstly, the guiding and driving system of the movement of the safety cover is simpler and lighter than a guiding and driving system of the gripping tool. Secondly, the present invention allows the arrangement, if desired, of an additional upward stroke (with reference to Figures 1 and 2) of the movable portion of the safety cover, in such a way that, in its raised position, the movable portion creates a safety barrier, above the walls of the container.
Furthermore, as will be seen in more detail below, the system according to the invention provides a preferred embodiment wherein the operative unit 4 (in the example shown, the gripping tool 4) is also movable at least in one direction orthogonal to the main direction A, so that when the movable portion 5B of the safety cover is raised, the operative unit 4 can be moved outside the footprint of the containment volume of the movable portion of the safety cover. In this way, the performance of the operative unit is not reduced due to the size of the safety cover. As indicated, this aspect will be discussed in greater detail below.
The configuration of the support frame 3 in the case of the specific example shown here is clearly visible in Figure 5, as this figure only shows the frame 3. The frame comprises an upper crossbar 300 and a lower crossbar 301, parallel and spaced apart from each other, which are rigidly connected by two lateral uprights 302 and a central upright 303, from which an overhanging beam portion 304 protrudes. Still with reference to the specific example illustrated, all the elements 300-304 are in the form of welded metal sheet elements, with a quadrangular cross-section. Above the central portion of the upper crossbar 300, a circular flange 305 is welded, used for rigidly connecting, by screwing, to the flange 106 of the wrist 105 of the robot 1.
On the sides of the two lateral uprights 302, two guide sections 306 are provided for the sliding guide in the main direction A of the movable portion 5B of the safety cover 5.
With reference to Figures 3 and 4, within the guide sections 306, respective shoes 500 are slidably mounted, rigidly connected to two side plates 501, which support the movable portion 5B of the safety cover 5. Each plate 501 extends in an essentially orthogonal plane to the general plane of the support frame 3 and has an upper portion 502 of a triangular profile, from which a front arm 503 and a rear arm 504 protrude.
The movable portion 5B of the safety cover 5 is illustrated by itself in Figure 7. It is in the form of a casing consisting of a sheet of metal or synthetic material wound on itself so as to have a front main wall 505, a rear main wall 506 and two end walls 507. The casing wall is rigidly connected (for example, by screwing or bonding) to inner bands 508 that are secured, for example by screwing, to the attachment end 509 of the arms 503, 504. As indicated above, the support structure of the casing 5B carries a sensorized coating, for example, having the stratified structure that has been described above.
The casing of the movable portion 5B of the safety cover is also secured to the attachment end 509 of two arms 510 forming part of a plate 511 arranged in an intermediate position between the two side plates 501. The plate 511 also has an upper portion 512 from which the two arms 510 protrude and which is directly controlled by an actuator 6 designed to drive the movement of the movable part 5B of the safety cover along the main direction A. The actuator 6 can be of any known type, for example, it can be a fluid actuator or electric actuator. The actuator body 6 is supported by the frame 3, having its ends rigidly connected to the upper crossbar 300 and to the lower crossbar 301 of the frame 3.
In the example illustrated, the actuator 6 is a pneumatic linear actuator of the non-stem type, including an outer body of fixed-length and a lateral slot from which a movable member protrudes, which is rigidly connected to the upper part of the intermediate plate 512. The constructive details of the actuator 6 are not illustrated here, since this actuator is of any known commercially-available type. A linear actuator without stem of this type is, for example, manufactured and marketed by the company Festo AG & Co. KG.
Still with reference to Figures 3, 4, from the crossbars 300 and 301 of the support frame 3, overhanging front brackets 307 and rear brackets 308 protrude, to which the casing of the upper fixed portion 5A of the safety cover 5 is connected.
The upper portion 5A of the safety cover is illustrated by itself in Figure 6. In this case as well, this portion of the safety cover comprises a casing consisting of a metal sheet or synthetic material wound on itself in order to define a front main wall 510, a rear main wall 511 and two end walls 512. The casing of the cover portion 5A is secured by means of screws or by bonding to circumferential bands 513 which are, in turn, secured to the attachment brackets 307, 308 as described above.
As with the portion 5B, the portion 5A also has a support casing that carries a sensorized coating, for example, having the stratified structure described above.
During use, the actuator 6 is operated to control a vertical movement (with reference to Figures 3, 4) of the movable portion 5B of the safety cover relative to the fixed portion 5A. As is evident from the above description, the actuator 6 directly operates the intermediate plate 511, whose connecting ends 509 are secured to the casing of the movable portion 5B of the safety cover. The movement of the movable portion 5B is guided both directly by the actuator 6, and by engagement of the shoes 500 carried by the lateral plates 501 in the two lateral guide profiles 306.
Still with reference to the specific example illustrated, the movable portion 5B of the safety cover 5 is precisely set in position and lockable, both in its lowered position and in its raised position, by engagement of a shutter pin 7 within a first hole 513 (Figures 3 and 10) or within a second hole 514. The holes 513, 514 are formed in the intermediate plate 511. The shutter pin 7 is driven axially by a pneumatic actuator 8 whose body is rigidly supported by the beam portion 304 (Figure 5) of the support frame 3.
Now with reference in particular to Figures 8-10, in the case of the specific example illustrated, the operative unit 4 is formed of a gripping tool including a lower support plate 9, of elongated shape, the plane of which is orthogonal to the main direction A, and which extends in parallel to a direction B, orthogonal to the direction A, and parallel to the crossbars 300, 301 of the support frame 3. The bottom plate 9 supports gripping tools 10 at its ends, which in the illustrated example are magnetic or electromagnetic.
The support plate 9 is slidably guided along its longitudinal direction B by means of the engagement of sliders 11 within guides 12 (see Figure 10) carried by an upper support plate 13 (see Figure 10 again) placed above the plate 9 (see also Figure 8 in particular). The plate 13 also lies in a plane orthogonal to the main direction A and has an elongated shape extending in parallel to the direction B. The plate 13 is slidably guided with respect to the support frame 3 in a direction C, orthogonal to both the main direction A and the direction B. The sliding assembly of the plate 13 with respect to the support frame 3 is obtained by means of engagement of sliders 14 carried by the plate 13 within guides 15 carried by the lower crossbar 301 of the support frame 3.
The movement of the support plate 9 in the direction B is controlled by two pneumatic actuators 16 (see Figures 4 and 8) rigidly connected below the plate 13. The two actuators 16 are used to control the movement of the plate 9 between a central position and two opposite extreme positions, each actuator being able to control the stroke between the central position and a respective extreme position. Of course, it would also be possible to adopt a single larger pneumatic actuator, which controls the entire stroke between the two extreme positions. The movement of the plate 13 in the direction C is controlled by a single actuator 17 (see Figures 3 and 9), which is rigidly connected to the support frame 3. The actuator 17 is also preferably a pneumatic actuator, provided that it is possible to adopt actuators of any type, particularly including electric actuators.
The operative positions of the plate 9 and the plate 13 can also be precisely set and are lockable by activating shutter devices. For example, Figure 9 illustrates a pneumatic actuator 18 carried by the plate 13, which operates a shutter pin 19, configured to selectively cooperate with holes 20 (one of which is visible in Figure 3) formed in elements integral with the plate 9 for setting into position and locking the plate 9 into its operative end positions. The operative positions of the plate 13 are also precisely settable and lockable by engagement of a shutter pin operated by an actuator 21 within holes 22 (one of which is visible in Figure 3) formed in elements integral with the plate 13. The actuators 18 and 21 can also be of any type.
Finally, the functional assembly of the illustrated example is provided with two actuators 23 (Figures 3 and 9), for example of the pneumatic type, which operate gripping hands 24 provided for safety, in addition to magnetic devices 10, to ensure that the piece P gripped by the tool cannot fall in the event of failure of the magnetic devices.
On the support frame 3, two control units E are also mounted on all the actuator devices which are provided by the functional assembly. In the case of the specific example illustrated, where the actuator devices are all of the pneumatic type, the control units comprise assemblies of solenoid valves for controlling the operation of the various actuators according to a predetermined logic programmed in an electronic control unit of the solenoid valves.
The functional assembly is also preferably provided with opto-electronic units H.
Figures 11 and 12A, 12B illustrate a schematic of the functional assembly described above, in the operative condition with movable portion 5B of the safety cover lowered (Figure 11) and in the operative condition with movable portion 5B in a raised position (Figures 12A, 12B, where Figure 12A shows a front view and Figure 12B shows a side view). Figures 12A, 12B show a condition in which, once the movable portion 5B of the safety cover has been raised, the gripping tool 4 can be moved transversally in both direction B (Figure 12A) and in direction C (Figure 12B) in order to move to the boundaries of the footprint area of the safety cover 5 (particularly of the lower portion 5B), so that it can also operate adjacent to a side wall of the container CT without risk of interference of the cover 5 with the container CT. The advantages of the invention from this point of view are made apparent from Figures 14-16. Figure 1a schematically shows - in a plan view- the container CT from which the assembly according to the invention must pick up the pieces. In Figure 14, the reference 5B indicates the footprint of the movable part 5B of the safety cover 5, when it is positioned in a corner of the container CT. Still in Figure 14, reference 4 indicates the footprint of the gripping tool 4 if this were to always remain at the center of the safety cover. As is evident, this condition would lead to the inability of bringing the tool 4 into contact with the walls of the container CT. The entire perimeter area that, in Figure 14, is dashed and indicated with reference NR would be unreachable (Not Reachable) for the tool. Figures 15 and 16 instead show that in the assembly according to the invention, thanks to the possibility of moving the tool 4 in the directions B and C, indicated in Figures 12A, 12B, the tool 4 can come into contact with any of the four corners of the container or, of course, in any intermediate position between those shown, in which the tool is adjacent to a single wall of the container CT.
Figure 13 shows an embodiment in which the gripping tool 4 is connected to the support frame so that it can also be rotatable at least about one axis 30 with respect to the fixed frame 3. The example illustrated refers to the case in which a spherical joint is provided. Figure 13 shows an additional advantage of the functional assembly according to the invention. As can be seen, the movable portion 5B of the safety cover can be arranged to have a raised position in which it can protrude above the fixed portion 5A. In particular, it is thus possible to arrange the movable part of the cover 5 in such a way that it overlaps in height and surrounds the end of the robot so as to increase the degree of safety in the area where the robot operates.
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention.

Claims

A functional assembly for an industrial machine, in particular for a robot, said functional assembly comprising:
- a support frame (3), provided with a flange (305) for attaching to a robot wrist (105) or other element of an industrial machine,

- an operative unit (4), for example, a gripping tool or an operator tool, supported by said support frame (3),

- a safety cover (5) for said operative unit (4), which is carried by said support frame, and which defines a containment volume,

- wherein said functional assembly can assume a first operative configuration, wherein said safety cover (5) surrounds and covers said operative unit (4) and a second operative configuration, wherein said operative unit (4) is at least partially outside the containment volume of said safety cover (5),
wherein said safety cover (5) has a fixed portion (5A) rigidly connected to said support frame (3) and a portion (5B) movable along a main direction (A) with respect to the fixed portion (5A); said movable portion (5B) of the safety cover (5) being movable between a lowered position, wherein it surrounds and completely covers said operative unit (4), and a raised position, wherein said operative unit (4) is uncovered, and
wherein both the fixed portion (5A) and the movable portion (5B) of said safety cover (5) have a collaborative outer coating, equipped with proximity sensors and/or contact sensors,
said functional assembly being characterized in that:
- said movable portion (5B) of the safety cover (5) is movable outside the fixed portion (5A),

- said operative unit (4) is movable in two auxiliary directions (B, C) relative to said support frame (3), said auxiliary directions (B, C) being orthogonal to each other and being orthogonal to said main direction (A).

- said functional assembly comprises a first plate (13) slidably guided along the first auxiliary direction (C) on said support frame (3), and a second plate (9) carrying one or more operative tools (10), and guided on said first plate (13) in the second auxiliary direction (B) orthogonal to the first auxiliary direction (C) and the main direction (A)..
A functional assembly according to claim 1, characterized in that said operative unit (4) is movable with respect to said support frame (3) at least in one transverse direction (B, C) with respect to said main direction (A), in such a way that when said movable portion (5B) of the safety unit (5) is in its raised position, said operative unit (4) is movable in a position outside the footprint of the containment volume defined by said movable portion (5B) of the safety cover (5).
A functional assembly according to claim 1, characterized in that it comprises an actuator device (6) for moving the movable portion (5B) of the safety cover (5), an actuator device (17) for moving said first plate (13) and an actuator device (16) for moving said second plate (9), as well as a plurality of shutter devices (8, 18, 21) for precisely setting into position and locking said lower portion (5B) of the safety cover (5), said first plate (13) and said second plate (9).
A functional assembly according to any claim, characterized in that said operative unit (4) is supported in such a way to also be rotatable, at least about one axis (30) with respect to the support frame (3).
A functional assembly according to claim 3, characterized in that on said support frame (3), at least one control unit (E) is mounted for controlling said actuator devices and said shutter devices.
A functional assembly according to any one of the preceding claims, characterized in that in its raised position, the movable portion (5B) of the safety cover (5) extends above said attachment flange (305).
A functional assembly according to any one of the preceding claims, characterized in that said operative unit is a gripping tool (4) for gripping pieces (P) in a container (C), characterized in that the dimensions and the vertical stroke of the movable portion of the safety cover are predetermined according to the size of the pieces to be gripped, so that once the piece (P) is picked up, the movable portion (5B) of the safety cover can be lowered into a position wherein the picked-up piece is contained within the safety cover.